StreamlineBar is a small add-on that remove clutter from your main action bar.
It removes some of the background 'textures' from the main bar (and XP / Rep bars), and optionally hides the bar end cap graphics and the various 'mini-buttons.'
When the mini-buttons are hidden, their functions can still be accessed through their keybindings. (i.e. 'p' will open your spell book, 'n' opens the talent window)